Electrolytic cell



Patented Jan. 26, 1943 'umraofsrA'ras PATENTZ OFFICE- ELECTROLYTIC 'CELL Theodore E. Abeel, South Dartmouth, Mass., as-

sigor to Aerovox Corporation, New Bedi'ord, Mass., a corporation of New York Application February 26, 1940, Serial No. 320,'791

7 laims. (Cl. 175-415) While the present invention has been particularly developed for and has special utility in dry electrolytic condensers of the prong terminal type, certain of the broader features thereot are of wider utlity with other electrolytic cells.

Among the objects of the invention are to provide a terminal structure for an encased electrolytic apparatus, in which a. soft metal is used in the unit and a harder metal for the terminal to meet the respective electrical and mechanical requirements and in which the connection between said diverse metals is so arranged as to preclude corrosion thereat that would result from any access thereto of electrolyte, particularly during operation. i

In a specific application the soft aluminum active parts of an electroiytic condenser are all mechanically protected within the interior of the casing and only the brass or other harder metal o'f the terminals protrudes from the casing, the bond between the, softer metal at the interior and the harder metal at the exterior being hermetically enclosed within the insulating cover to preclude access of electrolyte thereto and consequent erosion.

In the accompanying drawing in which is shown one of various possible embodiments of the relation oi' the terminal parts prior to assembly thereof, and

Fig. 6 is a detail sectiona view taken online 6-0 ot PIE. 2.

- Referring now'to the drawing, the condenser in general construction comprises a casing preferabiy of aluminum,tenclbsing a generally conventional dry eiectrolytic condenser roll n. That roll briefiy stated, may comprise four' sheets including two metal foils Il and |2 and two insulating interspacers !3 covering the opposite faces of one of' the foils, the four sheets being enrolled. Electrolyte lmpregnates the interspacers and maintains the conductive path between the electrodes, at least one of which has a dielectric coating formed thereon. In the usual electrolytic condenser application both electrode foils are of film forming material, preferably aluminum. Flexible terminal tabs protrude from the end of the roll for connection o! the electrodes into circuit. These flexible leads may be riveted or bonded to the electrode foils as for intance according. to the' disclosure of the prior patent to Georgiev No. 2,158,363 issued on May 16, 1939, or i! desired they may be integral with the respective foils, being slit therei'rom according to one'conventional practice.

minal lead IS from the continuous or cathode foil ll and three leads onevof which is shown at IS v from the respective three sections of the multiple wound anode foiis. The construction as thus far described being illustrative and entirely conventiona need not be more fully set forth.

The condenser is shown with an insulating cover I'l, carrying prong terminals s shown four in number, desirably of brass which may be nickel or chromium plated and, to which the respective fiexible leads IS and 16 are connected electrically and mchanically in manner to be 'more fully set forth hereinafter. The insulating cover l'l rests upon a peripheral shoulder s near the rim of the can, and in the com'pleted'assembly the rim of the can is rolled in as at 20 over the insulating cover and desirably over a peripheral rubber gasket 2| thereon.

According to the 'invention each flexible terminal lead li, IS of the active condenser unit is connected' to the corresponding terminal prong IQ by an intervening coupling piece'25 of the same metal as the electrodes, usually aluminum and desirably generaily cylindrical in contour.

The upper end of the coupling piece is formed with a. socket 28 preferably presenting a shoulder 21 upon which rests a flange 28 integral with the base end of the brass prong. the inner extremity The respective coupling pleces are accessible for contact connection at their inner ends with respect to the condenser roll. Desirably said coupling pieces protrude below said cover as shown. The flexible lead terminals II, II are connected by an aluminum-to-aluminum contact to the respective coupling pieces by suitable clamping engagement. Preierably the lower end of the coupling piece is formed with a socket I! therein, and the ends of the respective terminal strips IS, ii extend into the respective sockets and the said sockets are laterally collapsed to present two generally semi-cylindrical nesting jaws 32' and 32 between which the end of the terminal lead or strip is securely gripped al shown.

'As will be immediately obvious. the assembly is effected by amxing the respective prongs I! into the coupling pieces !I as described, molding the insulating cover ll thereabout, secureLv to house the prong and the aluminum base thereo! in such cover with the lower ends oi the coupling pieces protruding. Thereupon the flexibie terminal leads li, il of the active condenser unit are introduced into the corresponding sockets 32 of the coupling pieces and clinched in position as above described and shown in Flg. 4. Finally the condenser unit as thus connected to the cover is inserted in the can, the cover il laid upon the shoulder li. and the rim o! the can is rolled over at !I to complete the assembly.

Preierably the cover is molded with an integral .holiow axial stud 3! which has an integral ateral key :i that serves properly to position the respective prongs with corresponding contacts in the conventional socket in which the condenser structure is to be installed.

In the complete construction it will thus be seen that even with substantial now or seepage of electrolyte in heavy duty use, as for instance on continuous service in a hot room, there is no possibility of corrosion. For, no electrolytic conductive path is possible at the region o! contact between the diverse metals used. of aluminum for the interior, and brass or the like tor the external parts. The only metal parte accessible to electrolyte are the ioils with their tabs and the lower ends of the coupling pieces, all of 'which are of the same metal, aluminum. The area of contact between the brass or other harder metal terminal prongs with the aluminum coupling piece is completely and hermetically sealed in the embodiment shown, by being embedded in the interior of the molded cover l'| so that no electrolyte could possibly reach such region.

While the invention finds its preierred field of utility for dry electrolytic condensers of the prong terminal type, it will of course be mderstood that it is applicable to such condenser-s with other types of exterior terminals and that it could also be applied to advantage ior other types of electrolytic cells.

As many changes could be made in the above construction and many apparently widely difle rent embodiments of this invention could be made without departing !rom the scope of the claims. it isintended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limitin: sense.

Having thue described my invention. what I claim as new and desire to secure by letters Patent is:

. An, electrolytic condenser o! the plug-in 2,aoo,ses

type. comprising a casing having brass terminals, a dry electrolytic condenser unit therein, said unit comprising a pair o! aluminum roils, each with two or more flexible aluminum terminal leads protruding therelrom, an insuiating spacer intervening between said ioils, electrolyte carried by the same and of type subject to possible seepage in use, aluminum coupling pieces intervening between the respective tlexible leads and the brass terminals and eflecting electrical and mechanical connection thereot, said coupllng pieces having sockets at their outer ends, said brass terminals each having a flange near ita base end, !itting into the corresponding socket. the outer rims o! said socketed couplings being rolled over said flanges. a liquid-tight insulating cover mounting said coupling pieces, the inner ends o! said coupling pieces having sockets opening into the interior oi the ca'sing, said mckets mechanically embracing the ends of the respective terminal leads.

2. An electrolvtic condenser of the plug-in type, comprising a casing having a dry electrolytic condenser unit therein. said unit compelsing a pair ot aluminum toils, each with two or more ilexible aluminum terminal leads protnding theretrom, an insulating spacer intervenim between said foils, electrolyte carried by the same and of type subject to possible seepage in use, brass terminal prongs. aluminum bases thereior ecurely bonded thereto. an insulating cover carrying said prona and the bases thereot. said' aluminum bases protruding irom the inner !ece of said cover and presentlng sockets. the respective flexible terminal leads extending into said sockets and said sockets being collapeed !or secure'mechanical and electrical ensasement with said leads within the casing. Y

3. An eiectrolytic condenser ot the plug-in type, comprising a casing having a dry electrolytic condenser unit ther-ein, said unit comprising a pair of aluminum ioils. each with two or more tiexible aluminum terminal leads protrudng theretrom, an insulatins spa er intervening between said toils, electrolyte carried by the same and ot type subject to possible seepage in use, prongs oi' metal other than aluminum, aluminum ooupling piece: constituting socketed beses !or said prongs, a molded insulating cover embedding said socketed aluminum base; and the root ends ot said prongs, said aluminum bases protruding into the condenser casing !rom the inner face of the insulating cover and presenting sockets at the lower ends ther-eci, the respective ends of said flexible terminal leads extending into said sockets. said sochets being collapsed !or electrical and mechanical moment ther-eo! with the respective leads. I

4. In an electrolytic condenser, the combination o! a casing having a dry electrolvtic condenser unit therein. including aluminum !oil electrodes, an interspacer therebetween and electrolyte carried thereby and subjected to possible seepage during use. unitary tiexbe terminal leads protruding from said eloctrodeaan insulating cover havinl brass terminal prongs protruding !rom-the outer race thereoi, aluminum couplins p aces securely amxed to th base ends ot said prones. embedded in said cover and protrudingatthei-innerendsintosaidcasinmsaid flexible terminal leads being directly clamped in aluminum to aluminum contact with respect to said protruding ends o! the coupling pieces. the innerendsottherespectivealummumcoupling piecebeingintheiormofockemthetlexible asoases terminal leads in the form of !oil strips ex`- tending into said sockets, said sockets being longitudina11y.co1lapsed to clasp the respective terminal leads between two generally semi-cyiindrical shelis thus ormed.

5. A terminal assembly for an electrolytic cell comprising a fiexible terminal strip of soft metal,

a rigid terminal piece ot hard metal and a connector coupling joining said elements into a unitary structure, said connecter element having sockets lodging the' corresponding ends of the elements it connects and clamped thereagainst for secure mechanicai and electricai engagement thereof. v

6. A terminal structure for an electroiytic cell, comprising a flexible' aluminum terminal strip, an associated rigid brass terminal prong and an aluminum coupiing piece therebetween, said coupling piece having a socket lodging the base end of said brass prong, said socket being pressed securely against said prong to retain the same cure direct metal to metal enga geme'nt with against relative longitudinal and rotary dispiacement. said coupling piece having a socket et its opposite end lodgin the end of the flexible terminal strip, said socket being compressed for sesaid terminal strip. v

7. A terminal structure for an electrolytic cell, comprising a fiexible aluminum terminal strip, a brass prong having a flange near its root end, an aluminum coupling piece flrmly connecting the' prong with respect to the flexibie strip, said aluminum coupiing piece having a socket presenting a shoulder seating said flange, the rim of said socket being rolled over said flange, the` opposite end of said coupling piece having a socket lodging the extremity of said terminal strip, said socket being collapsed, securely to enage the end of said strip for intimate contact with opposite faces thereof.

-THEODORE E. ABEEL. 

